Various types of vehicle-resistant barrier gates have been employed to control the entry of vehicles into parking enclosures, or the like, or to control the passage of vehicles along roadways leading to restricted areas, such as parks, recreational areas, or other locations where there is restricted entry.
The locking mechanisms previously employed with such barrier gates have various disadvantages, such as requiring careful adjustment, being subject to rapid deterioration from adverse weather conditions, being expensive to fabricate or install, being vulnerable to tampering or theft, being usable only with gates swingable in one direction, being subject to frequent mechanical failure, being complicated in construction, and being difficult to operate.
One prior art device permitting the use of multiple locks for gates has been devised by the Pennsylvania Game Commission. This device uses a fabricated metallic box at the upper end of the gate post, which box is adapted to receive the end of the gate. The box has a hinged top through which access is gained. When the end of the gate is positioned within a horizontal opening in the box, a pin is then placed downwardly through openings in the end of the gate. The pin can either be maintained in place by two padlocks, one at the top and another at the bottom, or horizontal pins can be placed through the vertical pin in which case each of the two horizontal pins may then be held in place by two padlocks, thereby giving this device the capability of utilizing four padlocks.
The U.S. Forest Service, in a facility in Michigan, has used a gate lock wherein the gate post is merely provided with a horizontally extending bar capable of mating with a slot in the end of the gate. The end of the bar is provided with a removable pin through which a padlock may then be passed.
Another system is the type of pipe gate used on International Paper Company lands located east of Maine Route 27, north of Kingsfield, Maine. This device is somewhat similar to that shown in the Easley U.S. Pat. No. 2,856,220, discussed below. In this particular system, the gate post is provided with an element having top and bottom portions and into which the end of the gate is swung. With the gate then in position, a pin is dropped through the top part of the element, then through the end of the gate and then through the bottom element, which bottom element provides shielding for a padlock which locks through the bottom end of the pin. The bottom element of this device is shaped somewhat like the covered gate head 13 of the Easley patent. Other devices also exist of a somewhat similar nature, but constructed so as to permit the gate to be opened either way by passing entirely through the gate receiving element mounted on the gate post.
Possibly the most sophisticated gate locking mechanism heretofore provided is one recently designed by the U.S. Forest Service which uses multiple locking; square-tubing to repel pipe cutters; and is adjustable in length in the field without welding. In this device a box is provided at the upper end of the gate post. However, once again, as with devices discussed above, a vertical pin is passed through the end of the gate and the box and means are provided for a multiple lock mechanism in conjunction with the vertical pin.
The Ritter U.S. Pat. No. 2,707,125 shows a locking gate mechanism having a recessed post, with a horizontal locking bar slidably movable into the recess, the opening of which is controlled on the gate post. The device uses multiple locks and is quite sophisticated and complex in some regards. However, it is expensive and the locks are not shielded.
The Myers U.S. Pat. No. 2,986,829 is somewhat similar to the Ritter patent in that it also shows a gate locking mechanism having a recessed post, with a horizontal locking bar slidably movable by a lever pivoted on the gate.
The Wason U.S. Pat. No. 3,282,617 discloses a gate locking device wherein a padlock is employed to restrain the raising of a locking plunger. Kelley, U.S. Pat. No. 2,587,167 shows a gate latch having a horizontal spring-biased bolt engaging the sides of a recess in the adjacent post.
Also known is a fence gate locking device having a U-shaped locking element on the gate post which pivots side-to-side on a vertical axis to grasp the fence gate, and then drops downwardly when alignment is correct into a slot through which a padlock can be passed. One such device of this type is believed to be marketed by Page Fence Company.
A problem with the devices mentioned above which use vertical pins is that water will run down the vertical pin and in cold weather will freeze, thereby freezing the locks and preventing convenient unlocking of the locks when desired.
Another device available is a device known as the "Security gate kit for controlling access". The locking portion of this device is not believed to utilize any rotating members and the device is believed to suffer from many of the deficiencies noted above.
The device of the Easley U.S. Pat. No. 2,846,220 is, in some respects, a superior design. However, this structure does have points of weakness which may be attacked, such as the horizontal pin 14. It utilizes no rotating members and is limited in the number of locks utilizable; also, where more than one lock is desired, such as in the FIG. 6 embodiment, a separate protective enclosure is necessary for each lock.
Also of interest is the Linder U.S. Pat. No. 3,990,182, which relates to a locking device utilizing a stretched cable, rather than a swing gate.